Although vitamin D is an important fat-soluble vitamin that is essential in regulating calcium and phosphorous balance in a dog's body as well as promotes retention of calcium, thus aiding bone formation and nerve and muscle control, its excessive intake can lead to a condition known as vitamin D toxicity or vitamin D poisoning.
Puppies and young dogs are more prone to this condition although it can occur in dog of any age, size and breed.
Common symptoms of vitamin D toxicity are
Vomiting
Weakness
Depression
Loss of appetite
Increased thirst (polydipsia)
Increased urination (polyuria)
Dark tarry feces containing blood
Blood in vomit
Loss of weight
Constipation
Seizures
Muscle tremors
Abdominal pain
Excessive drooling